[TriLUG] automated Audio processing in Linux

[Marty Ferguson]

Jeremy

My dad has been using a linux utiltiy to archive his collection of old LPs.
It is able to locate the tracks, and identifies them via the dead space
between them.  He's using a fairly recent SuSE distro.

Therefore i think this is how you could treat captured radio files too.
I don't know what utility he's using, but it has a fairly
simple non-graphical menu interface, which at a minimum you
could use tcl/expect to drive, and perhaps may have a batch/script
interface.  I think this is going to be really simple to solve.

If I were to describe the processing, I would change your written
requirements
to read thus:

Record a continual stream of audio from the sound card.
Create files which are 1 hour in length without regard to content. These 1
hour files
are the input buffer.
On a 1 hour (or whatever) schedule, create the processed output files.
The full file name indentifies the time of the recording event.
The content of each file is only active radio traffic with "white space"
removed.

At worse,  you will need to "cat"/merge the files which overlap buffers.
To measure the energy level of the input audio stream in real time and
control
the recording this way would be more difficult, but I'm sure is implemntable
too.

Your call may be monitored for quality assurance purposes...
Marty

-----Original Message-----
From: trilug-bounces at trilug.org [mailto:trilug-bounces at trilug.org]On
Behalf Of Jeremy Portzer
Sent: Monday, March 22, 2004 9:17 AM
To: trilug at trilug.org
Subject: [TriLUG] automated Audio processing in Linux


Good morning folks,

I'm looking for some sort of software that will do automatic/batch audio
processing.  Here's what I'm looking to do:  connected to the input of a
sound card is a scanner radio which is listening to certain
frequencies.  Radio traffic is erratic, so most of the time there is no
input (or a very low level of white noise perhaps).

What I'd like to do is run something that would monitor the input ...
when there is traffic, record that into a file, and then stop recording
when the transmission stops.  This needs to be totally automatic; the
files would then be compressed and put on a web site (I can do that part
easily enough with shell scripts).  I also would like to be able to
stream the same incoming audio to icecast at the same time, for
real-time listening.

What kind of software is out there for batch audio processing in Linux?

Thanks for any advice.  My experience with Linux and multimedia stuff is
a bit limited, so I hope I can get this working!  I'm planning on using
Alsa (either with 2.4 or 2.6) but could change that if necessary.

Regards,
Jeremy

--
/---------------------------------------------------------------------\
| Jeremy Portzer        jeremyp at pobox.com      trilug.org/~jeremy     |
| GPG Fingerprint: 712D 77C7 AB2D 2130 989F  E135 6F9F F7BC CC1A 7B92 |
\---------------------------------------------------------------------/